The present invention relates to the extraction of vanillin from lignin fermented spent waste liquors using large pore, high silica/alumina ratio zeolite. More particularly the vanillin is extracted from fermented spent waste liquors by contacting these liquors with large pore, high silica/alumina ratio zeolites such as Beta, ZSM-20 or dealuminated Zeolite Y.
In spite of the well known properties of zeolites as a general class of adsorbents they have not heretofore been found suitable selective adsorbents for vanillin. More particularly, few of the known molecular sieve zeolites have pores large enough to admit molecules the size of vanillin and those that do, such as Zeolite X and Zeolite Y for instance, have a greater selectivity towards the molecules in the extract which are more polar than vanillin.